Fuel control systems for automotive vehicles determine an amount of fuel to inject into an engine cylinder based on certain engine parameters. Fuel delivery may depend on engine parameters such as air flow, engine temperature, and fuel burned in a preceding combustion cycle. For example, in cold engines, not all of the fuel injected into the engine cylinder is burned during combustion. Fuel that is not burned in a combustion cycle is referred to as “lost fuel.” Some fuel may be passed directly through to the exhaust without being burned. Additionally, some fuel may drip down the cylinder walls and mix with engine oil. Therefore, cold engines typically require more fuel to be injected than the amount of fuel to be burned to compensate for the lost fuel.
Generally, automotive manufacturers implement some form of compensation in the fuel control system to compensate for the lost fuel and/or “wall wetting.” For example, gain scheduling can be used to vary the compensation parameters over operating conditions of the engine. Alternatively, the fuel control system may add extra fuel to the fuel command to offset the lost fuel. However, current methods do not adequately determine lost fuel or non-linear fuel dynamics behavior.